Telephone system



Feb, 3. 1925; 1,524,665

E? W. LINCOLN TELEPHONE SYSTEM Filed May 31, 1921 Patented Feb. 3, 1925.

ELMEE w. LINCOLN; or -oH1oneo,-;iLLrnors, assrenon TO enr oeeswrrcnnonnn AND SUPPLY COMPANY, or onrcaeo, rumors, a ooiaronnrron' or rLLriiorsl' TELEPHONE 'SY Application filed May 31, 1921. Serial No,.,47;3,84,41.

T 0 alljwhom may concern:

Be it, known. that I, ELMER .W..L1Noo N, a citizen of the United States of America, andv I a. residentof Chicago, county of Cook, and,

State of. Illinois, have invented certain new and useful Improvements. in Telephone Systems, of which the following is a speci-. fication.

My. invention. relates to telephone systems and has todo more particularly with measured] service systems, for telephone lines, whereby a call init-iatechby .avsubscri'ber at a calling substation and. the. obtaining. of va response. at a called substation is recorded by a service meterindividual tothe line of the calling substation, and an object of my invention;is theprovision of an. improved circuit arrangement for accurately. record.-

ing completed.connectionsfrom a. calling substation.

A feature ofimy invention is the pro-- vision of .means whereby the service meter associatedwiththe calling substation is only actuated ;when the, connection established fro-lira calling substation is inconversational circuitwith the desiredparty.

Another feature ofnmy invention, is-the provision, of a key individual to each: cord,

circuit of an operators positio-n whereby thekey must first be thrown to.,its. listen: ing position, .which actuates means whereby the operators set is connectedato the. cord conductors so, that she may, determine whether the calling party has been connecteditoz the, rightcalled party, and this actuation of thekey toits listening position conditions apparatus sothatif thee-all is found to be rightly established the actuation of the key toits metering position will actuate the meansefor bringing, abouttheinvention operating; in ,connectionnvith a suitable telephone i system- In the drawing I illustrate;thencalling substation A connects d; at the (exchange ,with a llne, circuit .L, comprising the i usual line of.- operators tmay seiz e .;th e. call to, theiexclusion of theothers; In. addition to; this line,circui t apparatus l associate a isenvico meter SM with the line circuit, and this meter is. actuated 'COyIQOQIfCl the; completed calls of the calling substation A withwhich the 1 service meter: ESM tis associatedi The i cord; circuit C for; g interconnecting substations ispprovidedi with an answering plu AP and a; calling plug; GP, the said answering and. calling plugs AP? ft-llCluCP being. connectedv by the heavily- .marked talkingconductors; The answeringpend of the cord circ-uitsO is provided with the sleeve relay SL,.wh 1 ch;1s energ zed fin ser es with the'gcut-oifv relay OO ofthe line circuit L whenithe answeringplugAP is inserted intothe jack of the callingline. An answering supervisory. relay AS is also provided-which isenergized over the line,-,.and a list ening relay LS which. is energized rto conneGt the operators-set O .tothe cord conductors A link disconnect ,re'lay L1); is provided which is energized when the callingsubscriber 'replaces his receiver upon the.switjchhook to disconnect the cord conductors from the corn neoted line circuit associated ,with the-calling substationz so as to permit the calling substation to recall.- without awaiting the withdrawal of the answering plug rlgPjfrom the'jaokJ. The; sleeve relay-SL, is provided with high resistance; and, low-.- resistance windings and upon the actuation of the relay the high; resistancewwinding is shunted; providing secret service. The shuntingofnthis high resistance wind-' ing prevents; the sleeve relay 1 Shin another cord from being; energ ed, should'ano ther operator attempt tOrflDSWGI the call afterit has been seized by air operator, so that an ope ator a another :cor'd at cmpt ingxto seize the call after the first operator has con nected to the calling line is prevented from communicating with the subscriber, as the shunt of the low winding of the relay SL of the first cord prevents relay SL of the second cord from operating. As the second operator is not connected to the calling line, due to the relay SL of the second cord remaining at normal, her operators set is not connected to the cord conductors, and she, therefore, does not receive a response from the calling subscriber and withdraws the answering plug of her cord pair from the connected jack.

A ringing control relay RC is provided, which is energized when the calling plug OP is inserted into the jack of the called line, and the relay RC energizing closes a circuit for the sleeve relay SL, the sleeve relay SL remaining energized until the plug CP is withdrawn from the jack of the called line. A ringing interrupter relay RI is also provided, which is energized upon the energizatio n of the ringing control relay BC to connect the constantly rotating interrupter I in circuit with the said relay R1 to intermittently energize and de-energize the said relay to connect ringing current to the called line from the ringing generator G.

A calling supervisory relay CS is provided, which is energized upon the response of the called subscriber. A meter control relay MCR and a listening disconnect relay LDR are also provided for purposes as will be more fully hereinafter described. Answering and calling supervisory lamps AL and CL are also provided for the usual supervisory purposes. The answering supervisory lamp AL is also provided with means for flashing it to give the operator a distinctive signal when the called subscriber has answered to notify her that the call is to be registered. A key K, individual to the cord, is also provided, which is the usual two-way key, and is provided with a listening position LP and the metering position MP, for purposes as will also be more fully hereinafter described.

To the right of the drawing I have illustrated a called substation B, connected at the exchange with the line circuit L, comprising the cut-off relay CO, line relay LR, multiple jacks J and multiple signals S. ln addition is provided the service meter SM associated with the called line, for registering completed connections that are initiated from the substation B.

Having described in general the apparatus embodied in my invention, I will nowdescribe more in detail the operation of my invention as illustrated.

Assuming now that the subscriber at the substation A initiates a call, the removal of the receiver closes an energizing circuit for the line relay LR of the line circuit L from battery, through the left-hand winding of the relay LR, through the substation and back to ground through the right-hand winding of the said relay LR. The line relay energizing closes its alternate contact 2, establishin a circuit through the multiple line lamps S at a plurality of the operators positions.

Assuming that it is the operator associated with the cord circuit C that answers the call, the insertion of the answering plug AP into the jack of the calling line establishes a series energizing circuit for the cut-oii relay C9 of the line circuit L and the sleeve relay SL of the cord circuit C, over a circuit traced from battery through windings 3 and l of the sleeve relay SL, conductor 5, normal contact 6 of the link disconnect relay L1), sleeve contacts of the connected plug Al and jack J, to ground through the winding of the cut-ell relay CO. The cut-oil relay CO energizing opens the energizing circuit for the line relay LR, which relay restores and ellaces the multiple line signals S. The sleeve relay SL energizing closes its alternate contact 7, and the holding circuit for the sleeve relay Sli may now be traced from battery through the middle winding l ol? the relay SL, its alternate contact 7, and over the previously described path to ground through the cut-off relay C0. The upper, high resistance, winding 3 of the relay SL is shunted, this arrangement providing for secret service, as the sleeve relay SL of a second cord circuit will not operate in series with the cut-off relay 00 as the shunt of the low-wound winding 4; of the sleeve relay SL ol the first cord circuit renders inoperative the relay SL of any second cord circuit that may be connected by its operator. The closure of alternate contact 8 of the relay SL establishes an energizing circuit for the listening relay LS, traced from battery through the winding of the relay LS, conductor 9, alternate contact 8 or" relay SL, conductor 10, normal contact 11 of the listening disconnect relay LDR, conductors 127and 13, to ground at normal contact 14 of the sleeve relay SL. The closing of alternate contact 15 of the relay SL closes an energizing circuit for the answering supervisory relay AS, traced from battery through the upper winding 01 the relay AS, conductor 16, alternate contact 15 of relay SL, conductor 17, normal contact 18 oi the link disconnect relay LD, tip contacts of the connected plug AP and jack J through the substation, back through the sleeve contacts of the connected jack J and plug AP, normal contact 19 of the relay LT), conductor 20, to ground through the lower winding of the relay AS. The relay AS thus bridged across the cord conductors, supplying talking battery to the calling substation. The listening relay LS til) we -nee cord conductors, and theopera-tor may now inquire the Wants of the calling. subscriber.

Should another operator attempt to seize the call after the opera-torassociated' with the cord G is-connectedwthereto, the

low resistance path of the.wincling .4 ofthe sleeve relay SL prevents the. relay SL of the second corcl'fromcoperating, and the r-elaySL of the secondv cord circuit failing; to operate, the listeningrelay LS of the second cord remains at. normal and theoperators set of the second cord is not con-p nectedacross. the cord conductors. The. second operator ,failingtto receive arrespo-nse when she answerslrno-ws thatthecall has. been answered by another operator and-1 Withdraws the plug of her cord circuit. from the jack of the calling line appearing at .her position. I

The cut-oii' relay C0 of the lineicircuit L and the service meter magnet SM. are multiply connected to the sleeve contact of the jack J, but the service meter. magnet.

ator inserts the calling plug GP into the jack J of the called line B, vand its 111-- sertion closes a series energizing circuit for the ringing control relayRG andlthe cutoff relay GO of the line circuit L from battery through the windings 24 and 25, O1'1(l110t01' 26, normal contact 27 of the sleeve relay SL, conductor 28, sleeve contacts of the connected'plug GP and jack J, to ground through the winding of the'cutoff relay GO of the line circuit L. The closing of alternate contact 29 of the relay HG establishes an energizing circuit for the sleeve relay SL, traced from battery, through the Winding of the relay SL, conductor 30, through alternate contact29 of the relay RG, conductor 28, sleeve contact of the connected plug GP and jack J to ground through the cutoff relay G0. The sleeve relay SL upon energizing closes its alternate contact 31, establishing a locking circuit for itself, traced from. battery through the Winding. of said. relay SL, its alternate contact 31, conductor 28, the sleeve contacts of the connected plug and jack GP and J to ground through the cut-off The operator having.

relayiGOfl The opening of normal contact 2? of relav SIX, upon its energizatiomiopens; the initial energizing. circuit for tlievrelay. RG, but due to the closure of alternatezcontact 32 0f the relay RG and the closure of alternate contact 33 of the relay SL1, a substitute energizing. circuit is established. for the said re-layRG, traced from. battery through: the lower Winding. 24 ottherelay RC, alternatecontact .32 of the relay RG, conductor 34,.normal contact 35 ofithe link disconnect relay LD, conductor 36, normal. contact 37 of thecalling. supervisory relay GS, conductors 38, 39 and..40, .to groundat alternate contact 33 or the sleeve relay SLC. The. opening ojt' normal contact.32 of the relay 'R-G opens the circuit oi thecallingsupervisory signal GL andprevents sai.cl- ..lainp from lighting at thistime, The relay SL energizing opens its normal con-e tact 14, interrupting, the energizingcircuit for the listening relay LS and-...the. relay LS restoringits alternative contacts22 and 23 are. opened to disconnect theopen. ators set 0 from the-cord conductors.

The closing of contact 41.01? the relay RIG establishes an energizing circuit fort-he. ringing interrupter relay RI, traced from. battery through the Winding, of the relay. RI, conductor 42, throughrontact 4-1,..to. ground through. the constantly rotating lIl-L terrupter I, and the ringing. interrupter relay BI is thus intermittently energized and de-energized to open and close its contacts-43 and .44. Theclcsing of. alternate contact. 43 =of. the relay RI connects .the. ringinggenerator G to the cordconcluctors, The ringing current which is. transmitted. to-tl1e calledsubstation .'B. may be traced, from .the ungrounded pole of. the. ringing. generator G, conductor 45, alternate contact 43 of. the relay RI, the. tipcontacts of the connected-plug,GP and, jack'rJ, through. the call bell. and condenseratthe called substation B,',ring scontacts of the connected plug, GP and jack J, to ground. through the alternate contact .44 ofthe relay RI. The closing ot alternatecontact 46 of the relay RI, also gives the calling,.sub scriber an, audible tone, notifying himv that the callecl for subscriber is being. signaled, said audible tone-beingtraced fromthe generator G through the coil 47 and=.condenser 48, through alternate contact 46 of the relay RI, conductor 49, back to the calling substation A.

The subscriber at the substation B, in response to his signal, removes his IBCGlVGl.

from the switchhook,and upon the closure of normal contacts 43 and 44 of the relay 'RI during one of the de-energizations of 50, normal cont-act- 44, the ring contacts of the connected plug GP and jack J, through the now closed contacts at the substation switchhook, back through the tip con tacts of the connected ack J, and plug GP, normal contact a3 of the relay RI, conductors 49 and 51, alternate contact 52 of the relay SL, conductor 53 to ground (through the upper winding of the relay GS. The relay GS upon energization opens its normal contact 37, opening the circuit of the ringing control relay RG, and the said relay RG upon deenergization opens its alternate contact 41, disconnecting the interrupter I from the ringing interrupter relay R1. thus preventing further energizations and de-energizations ot' the ringing interrupter relay RI, and the relay RI now remains at normal. The closing of alternate contact 37 of the supervisory relay GS establishes an energizing circuit for the meter control relay MGR, traced "from battery through the winding of the relay MGR, conductor 54, through the alternate contact 37 of the relay GS, conductors 38, 39 and 40, to ground at alternate contact 33 of the relay SL. The meter control relay MGR energizing closes its alternate contact 55 to establish a locking circuit for itself, traced from battery through the winding of the said relay MGR, its alternate contact 55, conductors 39 and 40 to ground at alternate contact 33 of the relay SL.

The closing of alternate contact of the relay MGR establishes a circuit for the answering supervisory lamp AL, traced from battery through the lamp AL, normal contact 61 of the listening disconnect relay LDR, conductor 62, normal contact 63 of the key K,

conductor 64, alternate contact 60 to ground through the constantly rotating interrupter I. This circuit, closed for the answering supervisory lamp through the interrupter I, brings about the flashing of the said lamp AL and indicates to the operator that the called-for subscriber at the substation B has answered and that the subscriber at the calling substation A and the subscriber at the called substation B are now in conversational circuit and that the call which has been initiated by the calling subscriber at the substation A is ready to be registered. Before the call can be registered the operator must actuate the key K to the left to place it in listening position LP, which ac tuates means which again connects the operators set 0 to the cord conductors so that she may listen in on the connection and find out whether the connection established is the connection that was called for, or whether there was a mistake made in the called parl'ys number. Should this be the case, the operator removes the calling plug from the jack and inserts it into the proper jack of the wanted line. The actuation of the key K to its LP position closes an energizing circuit for the listening relay LS (which it will be remembered, was restored when the sleeve relay SL energized due to the insertion of the calling plug GP into the jack J of the called line), from battery through the winding of the listening relay LS, alternate contact 8 of the relay SL conductor 10, normal contact 11 of the listening disconnect relay LDR, conductor 12, alter nate contact 65 of the key K, conductors 6'6 and 67, to ground at alternate contact 68 of the relay MGR. lhe listening relay LS upon energization closes a locking circuit for itself, traced from battery through the winding of the relay LS, alternate contact 8 of the relay SL, conductor 10, normal contact 11 of the relay LDR, conductor '69, normal contact 70 of the key K, conductor 71, alternate contact 72 of the listening relay LS, conductor 67 to ground at contact 68 of the relay MGR. The closing of alternate contacts 22 and 23 of the listening relay LS again connects the operators set 0 to the cord conductors, and she may now listen in on the conversation; and assuming that the right connection has been set up and that the subscriber at the substation A and the subscriber at the substation B are now in conversational circuit, the operator now ac tuates the key K, by moving it to the right into its metering position MP, to bring about the registration of a completed call on the service meter SM associated with the callin subscriber at the substation A. The key K is so constructed that when moved to its metering position MP its normally open contact 75 is closed first, and the closing of the contact 75 closes a circult for the service meter SM associated with the calling substation A, traced from the ungrounded pole of the direct current generator G, alternate contact 76, conductor 77, alternate contact 75 of the key K, conductor 78, alternate contact 79 of the listening relay LS, oOIltlUCtOI 80, winding 81 of the sleeve relay 5L, alternate contact 7 of the relay SL, ,onductor 5, normal contact 6 of the link disconnect relay LD, sleeve contacts of the connected plug AP and jack J, conductor 82, through the magnet of the service meter SN to ground. The direct current generator G may be from eighty to one hundred volts and is for operating the meter magnet. The purpose of the lower winding 81 of relay SL is for maintaining the relay SL energized and since the current flowing through conductor is eighty to one hundred volts and the current from battery through the middle winding at of said relay SL is of a lower voltage, the said relay SL would drop back due to this ditl'erence in the voltage, for in this case the current through conductor 80 will tend to overcome the current through a locking circuit for itself, traced from ground through the Winding 85 of the magnet, alternate contact Set, conductors 86 and 82, the sleeve contacts of the connected plug AP and iack J, normal contact 6 of the relay LDi conductor 5, alternate contact 7 of the relay SL, through the Winding 4 ot the relay SLT to battery. The service meter magnet. is locked up over this circuit and another registration of the service .meter 'tacts 2.2 and 23..

cannot be brought about due to this lookup condition of the' magnet, and the-service meter SM will remain insuch condition until the cord plug APis disconnected from the jack J, which Will restore the circuit to normal and place the meter in condition to register another call, or when the link disconnect relay Ll) operates to operatlvely disassociate the: cord circuit from the calling relay LD; as will be more fully hereinafter described.

The closine of contact 90 of the key 1:

when moved to its metering position Ml establishes an energizing. circuit for the listening disconnect relay LDR, traced'trom battery through the Winding otthe said rclay LDR conductor 91. alternate contact 90 of the key K, conductor 71, alternate (ontact 7201: the listening relay LS, con ductor 67, to ground atalternate contact-68 of the meter control relay htCR. The relay LDR energizing closes its alternate contact 92, establishing. a locking circuit for itself traced from battery through the Winding of the relay LDR, its alternate contact 92, conductor 93,-to ground at alternate contact 94E of the relay SL. The opening of normal contact 11 of the relay LDR opens the energizing circuit of the listening relay LS, and the relay LS restores to normal and again disconnects the operators set 0 from the cord conductors at its conpreventing the operator from again coming in on the connection,- thus providing secret service after the com pleted call has been registered upon the meter of the calling substation A;

The key K is constructed so that the contact is-closed first in order that a flow of generator current from generator G' may be transmitted to the magnet. of the service meter SM" to register the. same, and, as this circuit extends through alternate contact 7911f the listening relay LS, this relay must be held up momentarily so that this short impulse of generatorcurrent may be transmitted to" the said'magnet. Thus, contact 75 is closed before contact andassoon as contact 90 is closedthe circuit for the listening. disconnect relay LDR is established, and the opening of normal contacti 11 opens the circuit of the'listening relay LS to'disconnect theoperatofsset G from the cord conductors, and the openingi'o'falternate contact 79'of relay LS prevents further generator current: from flowing through the magnet of the service meter SM.

The key K when actuated into listeninc'= position Ml, aspreviously describethopens normal contact 63, which interrupts the flashing cir hit of the answering supervisory lamp AL, and when the key K is. thrownto its metering position. Mlflfthe listening disconnect relay L'DR is.energizech andthe opening of its normal contact 61 opens the circuit of theanswering supervisory lamp AL and preventsi ts further flashing. The calling subscribed at the substation A: and the called subscriber at the substation 313 are now in conversational circuit, the saidcircuit being traced over the heavily marked conductors.

From the previously description it be seen that the operator cannot again get in on the connection after. m'oving ;tl'1e key K into its metering position MP, as the listening disconnect relay is nowenergized and locks up to ground through the alter:- na'te contact- 94; of relay SL, and relayS L remains energized until the calling plug CP is withdrawn: from its connected jack at thetermination of! conversatiolnaand further registering. of the meter SMv is also prevented due to the opening of alternate contact 79 of listening. relayLS, and su'b sequent operations of. the key K Will not effect further actuations otthe service meter SM nor effect the reconnection of the opera- .tors set- 0 to the cord conductors Assuming that the subscribers A and B. have finished conversation, the subscriber at the substation A' replacinghis receiver upon the switchhook, Vopens the energizing circuit through the answering supervisory relay AS at the sivitchhook contacts.. and the closing of normal contact 21. ot'the' answering supervisory relay AS establishes. I

a circuit for the answering supervisory lamp AL, traced from battery. through the lamp AL, alternate contact 61 otthe relay LDR, conductor 95, normalcontactr2l of relay AS, alternate contact:96.of the sleeve relay SL, conductors 39' and 40 to ground The closing of normal contactfll'iot of the said relay LD, conductor 97, normal contact 21 of relay AS, alternate contact 96 of the sleeve relay S-L, conductors 39 and 40 to ground at alternate contact 33, and the relay Ll) energizing opens its normal contacts 18 and 19, disconnecting the cord conductors of the cord circuit from the line circuit L, and allows the cut-off relay CO to restore, for purposes as Will be presently described. The sleeve relay SL has its initial energizing circuit opened at the normal contact 6 of the relay LD, but a substitute energizing circuit is establisherl for it, traced from battery through the Winding 4; of the relay SL, alternate contact 7 of relay SL, conductor 5, alternate contact 6 of the relay LD, conductor 98, through its alternate contact 96, conductors 39 and 40, to ground at alternate contact 33 of the sleeve relay SL.

The replacing ot the receiver at the called substation B interrupts the energizing circuit of the calling supervisory relay US at the switchhook contacts, and the closing of normal contact- 37 establishes an energizing circuit for the calling supervisory signal CL, traced from battery, through lamp CL, alternate contact 35 ot the relay LD, conductor 36, normal contact 37 ot the relay (7S, conductors 38, 39 and 40, to ground at alternate contact 33 of the sleeve relay SL. Should the called subscriber at B have replaced his receiver first, the de-energization of the calling supervisory relayCS closes an energizing circuit for the calling supervisory signal CL, tracedv from battery through the lamp UL, conductor 99, normal contact 32, conductor 34:, normal contact 35 of the relay LD, to ground at alternate contact 33; and when the calling subscriber at the substation A replaces his receiver, the

circuit of the said lamp CL extends through the alternate contact 35 ot the relay LD, previously described. The operator noting the two lighted supervisory signals AL and CL knows that conversa tion has terminated and withdraws the answering plug AP and calling plug GP from their respective jacks J and J.

Assuming that the calling subscriber at the substation A wishes torecall atter he has hung up, butbetore the plugs Al and (P have been withdrawn from their respec tive acks J and J the removal of the receiver at the calling substation A will bring about the energization of the line relay LR, as before described.

Upon the energization of the link disconnect relay LD, its normal contact 6 was opened, opening the series energizing circuit for the cut-off relay CO and the sleeve relay SL, and the cut-oil relay CO, due to this interrupt-ion of its circuit, restores to normal, and the closing of its normal contacts again places the line relay L'R under the control of the calling substation A, and the energization of the line relay LR, due to the removal of the receiver at the recalling substation A, brings about the closing of its alternate contact 2, which again lights the multiple line signals S before a number oi operators positions, and any one off a plurality of operators or the operator that originally handled the call may answer this recall.

Assuming that a connection has been established between a calling subscriber at the substation A and the subscriber at the substation B, and that the call signal at the substation B is being actuated and that the calling subscriber at the substation A replaces his receiver upon the switchhook he tore the subscriber at the substation B answers, the replacement of the receiver at the calling substation A opens the energizing circuit of the answering supervisory relay A and the closing of normal contact 21 oi? the relay AS establishes an energizing circuit for the link disconnect relay LD, as previously described, and the relay Ll) energizing opens its normal contacts 18 and 19 and disconnects the cord conductors from the line circuit L of the calling substation A. The opening of normal contact 35 of the link disconnect relay LD opens the locle ing circuit of the ringing control relay RC, and the ringing control relay RC de-energizing, its alternate contact ll is opened, interrupting the circuit for the ringing interrupter relay RI, disconnecting the constantly rotating interrupter I from the circuit of the said relay RI, and the relay El restoring to normal, its alternate contact 4 is opened, preventing further application of ringing current to the call bell at the called substation B. Thus, the calling subscriber at the substation A controls the disconnection ot ringing current to the called. substation B any time before the subscriber thereat answers. The closing of normal contact 21 of relay AS also establishes a circuit for the answering supervisory lanrp AL, traced from battery through the lamp AL. normal contact 61 of relay LDR, conductor 62, normal contact 63 of the key K, conductor 64, normal contact 60 of relay MGR. conductor 95, normal contact 21 of relay AS, alternate contact 96 of relay SL, conductors 39 and 40 to ground at alternate contact 33 of relay SL, and the closing of alternate contact ot the relay LD closes an energizing circuit for the calling supervisory lamlp CL, as previously described. h loreover, the opening of normal contact 6 of relay Ll) effectively disassociates the me ter magnet SM from the circuits of the cord 0, so that it is impossible for a call to be recorded against the calling substation under these circumstances. The operator noting the two lighted signals, Withdraws the answeringaplng AP from the jaclr'J andthe calling plug GP from the jack J".

Returningiz'now to the point? where the calling subscriber at the substation A- hasreplaced his receiver andthe called sub+ scriber at the substation B hasreplaced his after thetermination of conversation; the two supervisory lamps AL and GL are lighted, as previously described, and the operator noting the two lighted signals- Withdra-ws the plugs :from the i acks; The withdrawal Of calli'ngJplugGP from the jack J opens the energizin'gmircuitof theslee e relay- SL and thefisleeye relay SL restoring to normal opens itsalternate: contact' 33; and the interruption of this alternate contact 33:opens--the= locking circuitof the meter C'11t10'l I'6'lfly N[@R The int erruptioir of alternate-contactalso interrupts the energizing: circuit; of *the sleeve relay SL of the answering end :of'tlre cord circuit C, and the opening of alternate-contact 96' 0t the sleeve relay SL opens the energizing'circuit oi the link disconnect relay LD, and the withdrawal oftheanswering plug; AP and jack J of the calling line disconnects the cord circuit-if-rom-the-line -circuitL, and the apparatus used 111 establishing. the connectioirbetweenwthe calling: substation A and the called substationB is-now at normal and available tor use 111 I establishingother connections;

The energization of the link disconnectrel a y LD upon the replacement otthereceiver at the calling substationwA, as--p1i'ei ously described; opens its normal contact (3. and the opening of its con-tact (if' inten' ru-pts the loc'kin-gf'circuit which: extends through th'e lett-hand W'inding85 of the magnet of the service meter Slit andthe magnet otthe SQIVIGG-flYlQl'zB-P now"1'estores to I normal so that, should the calling subscriber at the 'substatioirA WlSlltO recall the re 1uo\"al=of 'thereceiver at the-r substationpe-n mits the lighting of theline sig-nalss, so

that when another call froin the recalling substation- A: to that. of a called line has been established, the operator that-h as established thisrecall.connectionmay actuate the service meterto reg ster a call a gainst the said recalling subscriber; 1

Should the operator attempt toregister: a

scriber= to attract theoperators attention to is closed for it" due 'to therelay- BS *reinain mg unenergized;land as 'its cont'act: m -fails to close, rel'ayiLDR ren'iain's at normal: It is thusseen that the key K must b'e-"m o\' ed to its listening position first before the call can be registered. 7 W'hile l hare-deseribedmy invention 0p crating in connection with a certaincircuit arrangement; I do notwish to be limited to the same; as changes: and modifications ma readily suggest themselves tothose skilledin themrt iand' I, therefore yaim lJO COVBD all such changes and smodifi'cationsas' com'ef within th'e tspirit andnscopie of the appended claims;

Having describeduny invention what -I claim as new and desire to secure by United States Letters Patent" is:

1i i A telephone; system inclu'dingla pair of? connected-telephone lines; an operatorFa'e tuated service 'meter, means for giving: the" operator a special si-gn-alithatza ca lli s ready to be metered; and" automatic mean s con trolled: by the calling: subscriber 'for auto matica-lly severing the' connection ofc'saidi pairof:lines;-

2: A" telephone system including? pair Of connected telephone: lines,\ an: operator control led service -meter, a special signalimeans actuated by the response of the called su'h the duty of mete g, and' automaticzmeans controlled :by the allin-gsubscriber for automaticallysevernrgthe connectiouu of said pain of lines. i

3. A telephone system inclu-(ilingia 'pair -of connected telephone lines; a switchboard 0p-v era toricont rolled service meters air answering superrisory signal and-means for: flash inl t it to signal the operator to opera-te'said service meteig said means efFective onthorcsponse of he calledsubscriber.

4:; In a. tBlQPhOMEVSVSlJBUB 331E answering supervisorysignal idispl ayed by; a switching operation performed at: the called substa tion; and autonzi-atic means; con trolled by? the calling subscribertt'or renderingixsaid signal non-responsive to the operation perform-ed at said:callcdisubstatio I 5. In at telephone system;- an answering supervisory lamp,- interruptei means-at the exchange for flashing it. a. switch; at the called substatiim for opera-tion to connect said means in circuit withsaidlamp, and automaticmeans controlled by. the calling subscriber for preventing the connection of, said means in circuit. with saidslamp.

6. A telephone system including a pair of connected telephone lines, a service meter, operator actuated switch 131821 113 forv operating the same, and a relay for excluding the 125 operators telephone from the connection, said relay con rolled by said switch means.

7. A telephone system including a pair of telephone lines, an operator controlled link circuit for connecting them having an operators telephone set automatically connected with the calling line on connection of said link circuit and line, and a manually operated listening kev for said link circuit effectively operable after the response of the called subscriber.

S. In a telephone system having operators to connect the lines, means automatically effective on connection made with the called line to disconnect the operators telephone set, a switch at the called substation for giving the operator access to the connection, and automatic means for freeing the calling line from the called line.

9. In a telephone system, an operator controlled link circuit connecting a pair of lines, an operator actuated meter, and switch means effective on actuation of said meter to maintain the operators talking set excluded from the connection.

10. A telephone system including a pair of telephone lines connected by an operator controlled link circuit, a listening key giving the operator access to the completed con I nection, an operator controlled service meter, and a switch effective on actuation of said meter to render said key ineffective for listening.

11. In a, telephone system a manually operated listening key effectively operable after the called subscribers response, a service meter and means for actuating it, said means serving to operatively disable said listening key.

12. In a secret service telephone system, means for allowing an operator access to a completed connection to see if the call is ready for metering, and switching devices preventing her talking set thereafter from being connected.

13. In a telephone system, a calling line and an operator controlled link circuit hav ing a listening relay automatically effective on connection of said link circuit and said line, a called line for connection with said calling line over said circuit, a relay controlled over the called line when said lines are connected and an electrically oper- 'ated service meter having a circuit controlled jointly by said relays.

14. In a telephone system, an electrically operated service meter, a pair of connected telephone lines, an operators listening key, a relay controlled by the response of the called subscriber, and an operators switch for actuating said meter effective only by the throwing of said key to listening position following the control of said relay affected by the response of the called sub scriber.

15. A telephone system including a telephone line, an electrically controlled service meter, an operator controlled link circuit, said meter operable over a circuit including a conductor of said link circuit, a conductor individual to said line, switch means con trolled from the substation of said line to open said conductor of said link circuit, said link circuit remaining connected with said line, and a combined listening and meter control key for said link circuit for controlling said service meter after the response of the called subscriber.

'16. A telephone system including a telephone line, an electrically controlled service meter, a link circuit temporarily connected with said line, a service meter circuit including a portion of said link, and a terminal contact of said line, means controlled by the substation switchhook to cause said line to test idle while said link circuit is connected therewith, a contact of said means in said service meter circuit, and a combined listening and meter control key for said link circuit for controlling said service meter after the response of the called subscriber.

17. A telephone system including a calling line, an operator controlled link circuit, a relay for said link circuit serving to automatically connect the operators telephone with said line on connection of said link circuit and line, fan electrically operated service meter in a circuit including a switch contact of said relay, and means for operating said meter.

18. In a telephone system, a pair of connectedtelephone lines, an electrically controlled service meter, an operators telephone set, means for connecting it to a completed connection, devices at the exchange controlled by the response of the called subscriber, a circuit for said meter effectively operable only after the connecting of said telephone set, following the control of said devices by the response of the called subscriber.

19. A telephone system including a pair of connected telephone lines, an electrically operated service meter, a manually operated switchboard operators switch for actuating said meter, an operators telephone set, and automatic switching devices effective by the operation of said switch to exclude said telephone set from the connection.

Signed by me at Chicago,,in the county of Cook and State of Illinois, this 27th day ill) 

